Thanks for your time. I'd like to use the spindle for
this project. I don't need much torque but I'd like to have a steady rpm.
I'm exploring using the controller that comes with the HDD but there are a couple of problems (so far) that I see:
1) It looks like the controller needs to get a signal from the motherboard before it will start the motor. For example, if I connect just the power cable nothing happens until I also plug in the SCSI cable. I have no idea how to fake out the controller to get it started.
2) I'd like to be able to adjust the RPMs. This isn't quite so important but it'll be harder to make my clock accurate if I can't.
3) The controller board gets pretty hot, which means it's using a lot of power. I'm also a bit worried about it over-heating since I won't have a cooling fan.
If anybody knows how to solve those issues then I'd gladly use the supplied controller. (In case it matters, the drive is [was?] a Seagate 120GB Barracuda ST3120026AS.) If the circuit in the OP can get the motor spinning at a constant rate then it might be exactly what I want, especially if I can adjust it by tweaking the pot.
Why use a HDD spindle? One, I like the idea of re-using old parts. More importantly, it looks cool.